I have one question: in the Half Life 2 coast level (d2_coast_10 I think) featuring the lighthouse, in the small wooden cottage where the main battle site is I noticed areaportalwindows were used. However, instead of fading to black they slowly blurred the further you got away from them, until there was a view through the window similar to the gaussian blurred loading screenshots the game uses. I was wondering how this was achieved; did Valve use a foreground model for the areaportal or a custom texture, or maybe a special rendering shader/technique? Please let me know as I would quite like to use this effect in my maps.